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Biomedical subjects

T Fukami

Publications and source records attributed to T Fukami.

At least 37 records · Page 2Linked to original sources
PubMed1998

Detection rate of the cervical gland area during pregnancy by transvaginal sonography in the assessment of cervical maturation.

OBJECTIVES: To detect the cervical gland area during normal pregnancy, and to determine its detection rate and relationship with cervical maturation. DESIGN: This was a mixed longitudinal and cross-sectional sonographic study involving a total of 514 transvaginal scans performed for detection of cervical gland area and measurement of cervical length in 260 normal singleton pregnancies at 16-41 weeks of gestation. The conventional cervical maturation index was measured simultaneously by digital examination. RESULTS: The detection rate of cervical gland area remained practically constant until the 31st week of pregnancy, but significantly decreased thereafter. Highly significant correlations were noted between the detection rate of cervical gland area and cervical length, cervical gland area and cervical maturation index, and cervical length and cervical maturation index. CONCLUSIONS: This study showed for the first time that cervical gland area can be detected sonographically and that its absence might be a predictor of preterm labor.

Adolescent↗
PubMed1998

A potent neuropeptide Y antagonist, 1229U91, suppressed spontaneous food intake in Zucker fatty rats.

Neuropeptide Y (NPY) is one of the most potent orexigenic substances known. 1229U91 was found to be a potent and selective NPY antagonist. To elucidate a physiological role of NPY in hyperphagia in obese animals, we studied the effect of 1229U91 on spontaneous food intake in obese and lean Zucker rats. The food intake of Zucker rats was suppressed by intracerebroventricular administration of 1229U91 more potently in obese than in lean animals without abnormal behavior (31.7 and 67.3% inhibition at doses of 10 and 30 micrograms, respectively, in Zucker fatty rats and 22.2% inhibition at 30 micrograms in lean rats). This compound markedly suppressed NPY-induced food intake at 30 micrograms but did not affect galanin-induced food intake, suggesting that the feeding suppression seen in Zucker fatty and lean rats is pharmacologically and behaviorally specific. These results suggest that NPY is involved in feeding behavior in Zucker fatty rats and that NPY contributes to feeding to a greater degree in Zucker fatty than in lean rats. The hyperphagia in Zucker fatty rats may be due to the abnormal overactivation of the NPYergic system.

Animals↗
PubMed1996

Ultramicro-analysis by use of light-scanning photoacoustic densitometry for electrophoresed protein in human hair.

A technique was developed for the ultramicro-analysis of proteins electrophoresed by Laemmli's method using a light-scanning photoacoustic densitometer. After electrophoresis, the proteins were blotted on a nitrocellulose membrane filter and colored by the avidin-biotin complex method. This filter was then measured using a photoacoustic densitometer. The optimal blotting time was 150 min. The relative standard deviation of four measurements was 3.89% for 200 ng bovine serum albumin (BSA). The limits of detection were 2.3, 0.69, 4.4, and 2.9 ng (S/N = 3) for BSA, ovalbumin, carbonic anhydrase, and alpha-Lactoalbum respectively. Proteins eluted from hair by various harmful agents, such as a surfactant and UV irradiation, were analyzed by the present method. Using 2-mercaptoethanol, the molecular weights of proteins in hair were in the range of 14,000-64,000. Maximal elution of protein was obtained at pH 8. More protein was eluted under alkaline conditions than under acidic conditions. A protein of Mr 68,000 was eluted from hair by oxidative treatment with either UV irradiation or sodium bromate.

Acoustics↗
PubMed1996

Synthesis and structure-activity relationships of 2-substituted D-tryptophan-containing peptidic endothelin receptor antagonists: importance of the C-2 substituent of the D-tryptophan residue for endothelin A and B receptor subtype selectivity.

Continuing studies on modifications of potent cyclic pentapeptide endothelin (ET) receptor antagonists, represented by BQ-123, and potent linear tripeptide derivative ET receptor antagonists, represented by BQ-788, are described herein. The introduction of D-tryptophan analogues with C-2 substituents in these peptidic ET antagonists resulted in potent ET receptor antagonists with various ETA/ETB subtype selectivity. Combined ETA/ETB receptor antagonists were found in both cyclic pentapeptide and linear tripeptide series with 2-halo- and 2-methyl-D-tryptophans. In contrast, compounds with 2-cyano-D-tryptophan were ETB receptor-selective antagonists. The C-2 substituent of the D-tryptophanyl residue appeared to be very important for the discrimination of ETA/ETB subtype selectivity of the antagonists. The potent ET receptor antagonists with various ETA/ETB subtype selectivity synthesized in this study may be useful tools for elucidating the physiological and pathophysiological roles of ET and ET receptors.

Animals↗
PubMed1996

Cyclic pentapeptide endothelin A receptor antagonists with attenuated in vivo clearance.

A series of analogues of BQ-123 (1), a potent cyclic pentapeptide endothelin A receptor antagonist, with amino acids linked to the side-chain of the Pro residue via an ester linkage was synthesized. All analogues synthesized exhibited potent endothelin A receptor binding affinity similar to that of 1. Of the synthesized analogues, the Lys, Arg and N alpha,N epsilon-dimethyllysine analogues, 9d-f, exhibited about a three-fold attenuation of in vivo clearance compared with 1. In rats, these analogues exhibited a 3-fold-higher plasma concentration and a longer retention time in plasma as compared with those of 1. The attenuated in vivo clearance was thought to be a consequence of decreased extraction of the compounds from the blood via the hepatic anion transport system, which efficiently extracts 1 from the blood.

Amino Acid Sequence↗
PubMed1996

A rare case of severe acute pancreatitis complicated with pancreatic pseudocysts, obstructive jaundice and intraperitoneal hemorrhage.

A 58-year-old man visited our hospital because of back pain. Blood examinations revealed the presence of acute inflammation and an increase of pancreatic enzymes. Abdominal computed tomography indicated pseudocysts in the pancreas. The patient was diagnosed as having acute pancreatitis with pseudocysts formation. During the course of the disease, a newly formed pseudocyst in the pancreatic head compressed the common bile duct, leading to the obstructive jaundice. In addition, the rupture of a pseudocyst in the pancreatic tail caused intraperitoneal hemorrhage. This is an interesting case of acute pancreatitis with pseudocysts in which two rare complications developed.

Acute Disease↗
PubMed1996

[Central retinal vein occlusion after embolization for spontaneous carotid cavernous sinus fistula].

A patient with spontaneous carotid-cavernous sinus fistula, who developed central retinal vein occlusion (CRVO) after interventional surgery, was reported. A 78-year-old woman was admitted with symptoms of right abducens palsy and conjunctival injection. Digital subtraction angiography (DSA) revealed bilateral carotid cavernous sinus fistulas supplied by dural branches of the carotid arteries. After embolization of the feeding arteries and the right cavernous sinus using PVA and platinum coils respectively, her symptom improved gradually. Six months after the embolization, she was readmitted because of blurred vision and abducens palsy on the left side. Engorgements of the cavernous sinuses and draining veins, and the shunt flow of the fistula were much less on DSA than those seen previously, but ophthalmologic studies showed an impending central retinal vein occlusion (CRVO) in her left eye. Prognosis of CRVO is generally poor. We discussed the mechanism of CRVO occurring after interventional surgery for CCF and the tactics for preventing it, and early detection of its development.

Aged↗
PubMed1996

Carrier-mediated active transport of BQ-123, a peptidic endothelin antagonist, into rat hepatocytes.

The hepatic uptake mechanisms and pharmacokinetics of BQ-123, an anionic cyclopentapeptidic endothelin ET(A) receptor antagonist, were studied in rats. Elimination of BQ-123 from plasma after intravenous injection of the compound was very rapid as evidenced by high total body clearance (CLtot, 50 ml/min/kg), which is comparable with hepatic blood flow rate. Within 1 hr after injection, 86% of the dose was excreted as its intact form in the bile. BQ-123 was taken up extensively by isolated rat hepatocytes both Na(+)-dependently and Na(+)-independently. The Na(+)-dependent system transported BQ-123 with higher affinity than did the Na(+)-independent system (Km; 6 and 12 microM, respectively), but its capacity was lower (Vmax; 140 and 390 pmol/min/10(6) cells, respectively). Both uptake systems were found to be active transport systems because of explicit inhibition by metabolic inhibitors. BQ-485, an anionic linear tripeptide, strongly inhibited BQ-123 uptake with Ki values of 1.6 and 2.5 microM for Na(+)-dependent and Na(+)-independent systems, respectively, whereas BQ-587, a cationic cyclopentapeptide, inhibited BQ-123 uptake only slightly. Considering this in vitro finding and the low in vivo CLtot of BQ-587 together, the carrier systems for BQ-123 seem to recognize negatively charged substances selectively. Both Na(+)-dependent and Na(+)-independent uptake of BQ-123 were competitively inhibited by a bile acid (taurocholate) and an organic anion (dibromosulfophthalein). The Ki values were comparable with the Km values of taurocholate and dibromosulfophthalein transport, which suggests that the Na(+)-dependent system corresponds to the bile acid transporter and that the Na(+)-independent system corresponds to the organic anion transporter.

Animals↗
PubMed1995

Structure-activity relationships of cyclic pentapeptide endothelin A receptor antagonists.

Analogues of the natural product endothelin A (ETA) receptor antagonists cyclo(-D-Trp1-D-Glu2-Ala3-D-Val4-Leu5-) (1) and cyclo(-D-Trp1-D-Glu2-Ala3-D-alloIle4-Leu5-) (2) were prepared and tested for inhibitory activity against [125I]endothelin (ET-1) binding to protein ETA receptors. The DDLDL chirality sequence of the natural products appeared to be critical for inhibitory activity because conversion of either D-Trp or D-Glu (or both) in 1 to the corresponding L-isomer(s) abolished this property. Systematic modifications at each position of the natural products clarified the structure-activity relationships and led to highly potent and selective ETA receptor antagonists. Most replacements of D-Trp1 and Leu5 with other amino acids caused a significant loss of inhibitory activity. In contrast, replacement of D-Glu2 with D-Asp2 enhanced the activity. With regard to the Ala3 position, all analogues with imino acids, independent of being cyclic or acyclic, showed higher affinities than did the amino acid analogues. In addition, most replacements with amino acids, which had various functional groups in their side chains, did not significantly modify ETA binding affinity. The D-Val4/D-alloIle4 position was very important for inhibitory activity, and a beta-position branched D-amino acid or a D-heteroarylglycine was preferable at this position. Among synthesized cyclic pentapeptides, compound 36 (BQ-518) was the most potent ETA receptor antagonist, with a pA2 of 8.1 against ET-1-induced vasoconstriction in isolated porcine coronary arteries. This compound also showed the greatest selectivity between ETA and ETB receptors (IC50 for human ETA = 1.2 nM, IC50 for human ETB = 55 microM). In contrast, compound 8 (BQ-123) is a highly soluble, potent, and selective ETA receptor antagonist (pA2 = 7.4, IC50 for human ETA = 8.3 nM, IC50 for human ETB = 61 microM). The sodium salt of 8 is practically freely soluble in saline. These compounds are useful tools for not only in vitro but also in vivo pharmacological studies.

Amino Acid Sequence↗
PubMed1995

[3H]BQ-123, a highly specific and reversible radioligand for the endothelin ETA receptor subtype.

The mode of binding of [3H]BQ-123 (cyclo(-D-Trp-D-Asp-[prolyl-3,4 (n)-[3H]]Pro-D-Val-Leu)), an endothelin receptor antagonist radioligand, was evaluated in the human neuroblastoma cell line SK-N-MC at 37 degrees C. Scatchard analysis indicated the presence of a single class of [3H]BQ-123 binding sites with a high affinity of 3.2 nM. [3H]BQ-123 binding achieved steady state within 7 min and dissociated with a half-time of 1.4 min, while [125I] endothelin-1 binding barely reached a steady state even after 6 h and showed little dissociation. [3H]BQ-123 binding was sensitive to endothelin-1 and endothelin-2 (Ki values = 0.058 and 0.10 nM, respectively) and the endothelin ETA receptor-selective antagonist BQ-123 (Ki = 3.3 nM), while showing low affinity for endothelin-3 (Ki = 50 nM), the endothelin ETB receptor-selective agonist BQ-3020 (Ki = 970 nM) and other bioactive peptides. Thus, [3H]BQ-123 is a specific and reversible radioligand for endothelin ETA receptors. The rapid reversibility of [3H]BQ-123 binding should provide a tool for estimating the equilibrium inhibition constants (Ki values) of various compounds for endothelin ETA receptors.

Amino Acid Sequence↗
PubMed1994

Biochemical and pharmacological profile of a potent and selective endothelin B-receptor antagonist, BQ-788.

We describe the characteristics of a potent and selective endothelin (ET) B-receptor antagonist, BQ-788 [N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D -1- methoxycarbonyltryptophanyl-D-norleucine]. In vitro, this compound potently and competitively inhibits 125I-labeled endothelin 1 (ET-1) binding to ETB receptors on human Girardi heart cells (IC50, 1.2 nM) but only poorly inhibits the binding to ETA receptors on human neuroblastoma cell line SK-N-MC cells (IC50, 1300 nM). In isolated rabbit pulmonary arteries, BQ-788 shows no agonist activity up to 10 microM and competitively antagonizes the vasoconstriction induced by an ETB-selective agonist, BQ-3020 (pA2, 8.4). In rat, an ETA-selective antagonist, BQ-123 (1 mg/kg, i.v.), does not affect transient depressor response to ET-1 (0.3 nmol/kg, i.v.) but potently inhibits following sustained pressor response; vice versa, BQ-788 (1 mg/kg, i.v.) abolishes the depressor response, resulting in a rapid onset of apparently enhanced pressor response. Thus, being a potent and selective ETB receptor antagonist, BQ-788 may be considered as a powerful tool for investigating the role of ET in physiological and pathological processes.

Amino Acid Sequence↗
PubMed1994

Endothelin ETB receptors couple to two distinct signaling pathways in porcine kidney epithelial LLC-PK1 cells.

We characterized the endothelin (ET) receptor subtypes responsible for signal transduction in cultured porcine kidney epithelial LLC-PK1 cells. Both ET-1 (IC50, 43 pM) and ET-3 (IC50, 46 pM) inhibited the binding of [125I]ET-1 to LLC-PK1 cells to a similar extent. The binding affinity of LLC-PK1 cells was about 10,000 times higher for the ETB antagonist BQ-788 [N-cis-2,6-dimethyl-piperidinocarbonyl-L-tau-metylleucyl-D-+ ++Nin- methoxycarbonyltryptophanyl-D-norleucine] (IC50, 1.3 nM) than for the ETA antagonist BQ-123 [cyclo-(D-Trp-D-Asp-Pro-D-Val-Leu)] (IC50, 14 microM). ET-1 enhanced cyclic GMP (cGMP) production, but reduced vasopressin- and forskolin-stimulated cyclic AMP (cAMP) production. Both effects of ET-1 were antagonized by BQ-788, but not by BQ-123. The cAMP decrease, but not the cGMP increase, in response to ET-1 was inhibited by pertussis toxin, suggesting that the former response is mediated by pertussis toxin-sensitive Gi, whereas the latter is mediated by a pertussis toxin-insensitive G-protein. Therefore, the ETB receptors in LLC-PK1 cells couple to the two types of signal transduction cascades to reduce cAMP production and stimulate cGMP production via distinct G-proteins. ET-1 and probably also ET-3 may play a role in the regulation of renal epithelial transport by decreasing cAMP and increasing cGMP.

Amino Acid Sequence↗
PubMed1993

[Two cases of Swyer-James syndrome].

Case 1: 55-year-old male was admitted to our hospital for further examination of increased transparency of X-ray in the left lower lung. He had history of pneumonia in his childhood. Left bronchography revealed mild cylindrical bronchi-ectasia in the proximal bronchi but poor filling by contrast in the peripheral bronchi. Case 2: 61-year-old male was referred to our hospital with palpitation and dyspnea. Chest X-ray film revealed hyperlucency of the left lower lung. The ventilation scan showed a marked decrease in ventilation to the left lung and air trapping was present in the left lung. The perfusion scan showed a matched decrease in blood supply to the left lung. In both cases, pulmonary arteriogram showed narrowed and withered-tree-like left pulmonary arteries. From these clinical findings, we diagnosed these two cases as Swyer-James syndrome. We are reporting two cases of Swyer-James syndrome and describing the clinical feature, differential diagnosis and etiology of the syndrome.

Arteriosclerosis↗
PubMed1992

Biological profiles of highly potent novel endothelin antagonists selective for the ETA receptor.

We describe novel potent endothelin (ET) antagonists that are highly potent and selective for the ETA receptor (selective to ET-1). Of the synthetic analogs based on ETA antagonist BE-18257A isolated from Streptomyces misakiensis (IC50 value for ETA receptor on porcine aortic smooth muscle cells (VSMCs); 1.4 microM), the compounds BQ-123 and BQ-153 greatly improved the binding affinity of [125I]ET-1 for ETA receptors on VSMCs (IC50; 7.3 and 8.6 nM, respectively), whereas they barely inhibited [125I]ET-1 binding to ETB receptors (nonselective with respect to isopeptides of ET family) in the cerebellar membranes (IC50; 18 and 54 microM, respectively). Associated with the increased affinity for ETA receptors, these peptides antagonized ET-1-induced constriction of isolated porcine coronary artery. However, there was a small amount of ET-1-induced vasoconstriction resistant to these antagonists, which paralleled the incomplete inhibition of [125I]ET-1 binding in the membrane of the aortic smooth muscle layer. These data suggest that the artery has both ETA and ETB receptors responsible for ET-1-induced vasoconstriction. The antagonists shifted the concentration-response curve to the right for ET-1 in the coronary artery, and increased the apparent dissociation constant in the Scatchard analysis of [125I]ET-1 binding on the VSMCs without affecting the binding capacity, indicative of the competitive antagonism for ETA receptor. In conscious rats, pretreatment with the antagonists markedly antagonized ET-1-induced sustained pressor responses in dose-dependent fashion without affecting ET-1-induced transient depressor action, suggesting that the pressor action is mediated by ETA receptors, while the depressor action is mediated by ETB receptors. In addition, pretreatment with the potent antagonists prevented ET-1-induced sudden death in mice. Thus, these potent ETA antagonists should provide a powerful tool for exploring the therapeutic uses of ETA antagonists in putative ET-1-related disorders.

Amino Acid Sequence↗
PubMed1992

Analysis of responses to endothelins in isolated porcine blood vessels by using a novel endothelin antagonist, BQ-153.

We examined the effects of a novel ETA-selective endothelin (ET) antagonist, BQ-153, on vascular responses to ET-1 and ET-3 in isolated porcine coronary and pulmonary blood vessels, to clarify the roles of ET receptor subtypes in the regulation of vascular smooth muscle tension. With endothelium-denuded vascular tissues, the concentration-contraction curve (CCC) for ET-1 appeared as a single sigmoidal shape for all types of tissue. The CCC for ET-1 was antagonized by BQ-153 (2 and 10 microM) in all tissues, but part of the contraction was resistant. The CCC for ET-3 usually consisted of two different phases with higher (first phase) and lower (second phase) sensitivities to the peptide. Only the second phase of CCC for ET-3 was completely inhibited by BQ-153 (2 microM) in all tissues, while the first phase was resistant. The BQ-153-resistant contractile phases of ET-1 and ET-3-induced vasoconstriction appeared to have similar sensitivity in all tissues, and the contractile activity varied with each type of tissue. With endothelium-intact materials, the potencies of ET-1 and ET-3 for endothelium-dependent vasorelaxation in pulmonary artery were almost equivalent. BQ-153 (10 microM) did not inhibit ET-induced vasorelaxation. These results indicate that ET-induced vasoconstriction is mediated not only through ETA but also through ETnonA (probably ETB), and that the relative proportions of the ET-receptor subtypes mediating contractions vary in different vascular areas. In addition, results showed that ET-induced endothelium-dependent vasorelaxation is mediated through ETB.

Animals↗
PubMed1992

In vitro biological profile of a highly potent novel endothelin (ET) antagonist BQ-123 selective for the ETA receptor.

The novel endothelin (ET) receptor antagonists BE-18257A and BE-18257B were isolated from the fermentation products of Streptomyces misakiensis. The above-mentioned compounds inhibited [125I]ET-1 binding to ETA receptors (selective for ET-1) on porcine aortic vascular smooth muscle cells (VSMCs) with IC50 values of 1.4 and 0.47 microM, respectively. [125I]ET-1 binding to ETB receptors (nonselective to ET isopeptides) in cerebellar membranes was not inhibited by either of these compounds even at 100 microM. The synthesized analogue BQ-123 induced extremely potent inhibition of [125I]ET-1 binding to ETA receptors (IC50 of 7.3 nM), but it barely inhibited [125I]ET-1 binding to ETB receptors (IC50 of 18 microM) and binding of various other peptides to their receptors. BQ-123 shifted the concentration-response curve for ET-1 toward the right in porcine isolated coronary arteries, indicative of competitive antagonism for the ETA receptor. However, there was a small amount of BQ-123-insensitive vasoconstriction that paralleled the incomplete inhibition of [125I]ET-1 binding in the membrane of the vascular smooth muscle layer. These data suggest that the artery contracts via both ETA and ETB receptors and that BQ-123 selectively inhibits ETA-mediated contraction. Furthermore, BQ-123 revealed large tissue and species differences in the distribution of ETA receptors. Thus, the potent ETA antagonist BQ-123 should be useful in clarifying the (patho)physiological roles of ETA receptors.

Amino Acid Sequence↗